Jagged1 regulates extracellular matrix deposition and remodeling in triple-negative breast cancer

Abstract

<p>The extracellular matrix (ECM) and tumor microenvironment heterogeneity drive cancer progression and treatment resistance. High Jagged1 expression correlates with poor patient survival and promotes tumor growth and invasion in triple-negative breast cancer (TNBC). Using transcriptomics, proteomics, and imaging of cancer cell/fibroblast cocultures in vitro and in vivo, we demonstrate that Jagged1-mediated cross-talk between TNBC cells and fibroblasts enhances myofibroblast activation, collagen accumulation, and alignment of ECM fibers. In single-cell RNA sequencing data of TNBC tumors, high Jagged1 expression gives rise to a myofibroblast subpopulation previously associated with enhanced invasion. Jagged1 increases transforming growth factor–β (TGFβ) activity in fibroblast cocultures, and TGFβ inhibition prevents the Jagged1-induced ECM alignment. Thus, Jagged1 regulates ECM remodeling upstream of TGFβ. Furthermore, higher substrate stiffness up-regulates Jagged1, suggesting a feed-forward loop between Jagged1, ECM stiffness, and TGFβ. With the emergence of safe therapeutics targeting specific Notch components, Jagged1 modulation may offer an approach for treating invasive breast cancer.<br></p>